Steam-engine valve mechanism.



F. FOSDICK.

STEAM ENGINE VALVE MECHANISM.

APPLICATION FILED FEB. 5. 1914.

1,203,321. Patented Oct. 31,1916.

Fig.1. 8

Witnesses. lnvenIor.

FredericK FosdicK,

/ M moew Aflys.

FREDERICK rosmoK, or FITCHBURG, MASSACHUSETTS;

STEAM-ENGINE; VALVE MECHANISM.

Specification of Letters Patent;

Patented Oct. 31,1916.

Application filedrFebruarv 5, 1914. Serial No. 816,702.

To all whom it may concern Be it known that I, FREDERICK FosmoK, a citizen of the United States,'and resident of F itchburg, county. of Worcester, State of Massachusetts, have invented an Improvement in Steam-Engine Valve Mechae nism, of which the following description,

in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

This invention relates to steam engine valve mechanism of the general type shown in the patent to Frederick Fosdick, No. 569,628, granted Oct. 20, 1896, and No. 827,433, granted July 31, 1906.

The object of the invention is to provide a valve mechanism in which'the actuating cam shall have a revolving or oscillating movement thus securing an easy movement of theparts steadily andwithout shock or jar, in which the cam. portion of'the valve mechanism is located entirely within the steam chest thus reducing the number of stuffing boxes and requiring but a single.

of an engine with the improved valve mechanism applied thereto, Fig. 2 is a top plan view of the construction illustrated in Fig. 1.

In the construction of cylinder shown provision has been made for a steam jacket but this is shown for convenience, the invention being directed to the valve mechanism.

The cylinderis illustrated as provided with two ports arranged adjacent its opposite ends and shown respectively at 1 and 2. Each; of these ports is controlled by separate admission and exhaust valves. The admission valves are of the piston or other balanced type and are shown at 3. and a.

These valves are duplicates of each other and they are operated and controlled by mechanism which in duplicate. The exhaust valves are not illustrated because such illustration is ,uni lec'es sary' to. a disclosure of the present invention but the valve seats therefor are shown at 5 and 6 by meansof. which the ports 1' and 2 respectively. are connected with the exhaust chamber 7 in a familiar manner. The steam enters the steam chest through aninlet 8, passes into the chamber 9 which is infree connection with the chambers 10 and 11 at oppositev ends of the cylinder surrounding the admission valves. Each admissionvalve is mounted to slide in a chambered projection 12 or 13' projecting from the frame- Work into these chambers 10' and 11. When 7 the piston valves are in their outermost position connection is established from the chambers 10 or 11 through the port 1 or 2 with the engine cylinder and when these valves are in their innermost position such connection is cut off in a manner familiar to this type of valve mechanism.

Cap plates 15 bolted to the, exterior of the casing allow for the outward movement of, the admission valves. The valves are guided so as to have accurate rectilinear.

movement, thus eliminating any danger of undue friction, by means of large annular bearing members shown at 16 and 17 re-v spectively. These members are preferably of the same diameterv as the piston valves and are mounted to slide on ribs 18 pro jecting from the framework and forming on their faces bearing surfaces concentric with and in alinement with the bearing surfaces for the piston, or other valves. Each annu lar bearing member 16,17 is preferably made of a cup shape to give the required strength with a minimum amount of weight and is formed integrally with or rigidly secured to the valve stem. In the construc: tion illustrated the main portion of the valve stem is constituted as a hub or boss projecting centrally as at 20 from the bearing member toward its cooperating Valve and a slotted or yoke shaped lug 21 projecting. centrally from the bearing member in the opposite direction. The remainder of the valve stem consists of a rod 22 secured to the piston valve and screw threaded into, the hub 20 thus providing tor the adjustment of the valve. 2

"z admission valve.

A single shaft 23 extends centrally into the chamber 9 of the steam chest passing through a stufiing box 2% in the exterior wall of the steam chest. This shaft is given a, rotary or oscillating movement by the usual valve rod 25 operated in any suitable or usual manner from the. crank shaft or other moving part of the engine.

The shaft 23 has rigidly secured thereon within the chamber 9 of the steam chest a cam member 26 which consequently has'an oscillatory movement. This cam member is provided with symmetrically disposed cam surfaces 27, one for cooperation with each In the specific construction illustrated these cam surfaces are the walls of symmetrically disposed curved slots 28 formed in the cam member 26. The cooperation with the valves is secured through the medium of rollers 29 journaled in the slotted or yoke shaped lugs and riding in the slots 28, the Walls of the lugs 21 extending both sides of the cam member 26. Preferably also a spring 30 connected to the lugs 21 or other suitable yielding means serves to hold the rollers 29 in engagement with the cam surfaces 27 thus preventing any back lash.

The cam surfaces 27 are so shaped that the valves are started gradually from a condition of rest and are returned as gradually to this condition of rest so that there is an entire absence of any shock or movement to produce noise or excessive wear. This is secured by forming the lower portions of the cam surfaces 27 as shown in Fig. 1 of the drawings slightly eccentric to the axis of oscillation of the cam member 26. The valves therefore have a very slight and continuous movement during the period that the valves are closed and the valves are given sufficient lap to counterbalance or take care of this movement. T he upper portion of these cam surfaces viewing the construction as shown in Fig. 1 are given the required eccentricity with respect to the axis of oscillation of the cam member to secure the required opening and closing movement of the valves and preferably are of the shape shown in the drawing. The valves therefore are in motion at the beginning of the opening movement and at the end of the closing movement so that there is no shock or jar at this point.

The cam member 26 when oscillated thus gives precisely the same movement to each admission valve and gives it in a manner which insures an easy and smooth movement of the valve without shock or jar while the large annular bearing members insure the rectilinear motion of the valves without binding and with a minimum friction. The entire operating mechanism being located within the steam chest all stuffing boxes excepting the single stuffing box for the passageway of the shaft 23 inside the steam chest are eliminated, thus minimizing the leakage ofthe live steam. The construction is thus highly eflicient, of a simple nature and of great durability and strength.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. In a steam engine valve mechanism a pair of admission valves, oppositely disposed valve stems connected to saic valves to actuate them, annular bearing members on said stems and bearings therefor alined with the valves to prevent binding and un due friction. during the movement of the, valves, an oscillatory cam member provided with symmetrically disposed cam surfaces cooperating respectively with said stems, and means for oscillating said cam member to give the required alternate intermittent movement to said valves.

2. In a steam engine valve mechanism a pair of admission valves, oppositelydisposed valve stems connected to said valves to actuate them, annular bearing members on said stems and bearings therefor alined with the valves to prevent binding and undue friction during the movement of the valves and means for giving the required alternate intermittent movement to said valves.

3. A steam engine comprising a cylinder, steam admission valves, a steam chest, an oscillatory cam member located in the steam chest and provided with symmetrically disposed cam surfaces, connections between each valve and its cooperating cam surface, a shaft forsaid cam member extended through to the interior of the steam chest whereby but a single stufiing box for the valve mechanism is required, and means for oscillating said shaft to give the required alternate intermittent movement to said valves.

4. In a steam engine valve mechanism a pair of admission valves, an oscillatory cam member located in the steam chest and provided with symmetrically disposed cam surfaces, one for coiiperation with each valve, a portion of each cam surface being slightly eccentric to the center of oscillation to keep the valve moving but without opening the port and the succeeding portion acting to give the required opening or closing movement to the valve and means for oscillating said cam member to give the required alternate intermittent movement to said valves.

5. In a steam engine valve mechanism a pair of admission valves, an oscillatory cam member located in the steam chest and provided with symmetrically disposed cam surfaces, one for cooperation with each valve, a portion of each cam surface being slightly eccentric to the center of oscillation to keep the valve moving but without opening the port and the succeeding portion acting to give the required opening or closing movement to the valve, a shaft for such cam member extended into the interior of the steam chest whereby but a single stufling box for the valve mechanism is required, and means for oscillating said shaft to give the required alternate intermittent movement to said valves.

6. In a steam. engine valve mechanism a pair of admission valves, oppositely disposed valve stems connected to said valves to actuate them, an oscillatory cam member located in the steam chest and provided with symmetrically disposed cam surfaces, each valve stem having cooperative engagement with its adjacent cam surface, means for yieldingly holding each valve stem in cooperative engagement with its cam surface, and means for oscillating said cam member Copies of this patent may be obtained for to give the required alternate intermittent movement to said valves.

7. In a steam engine valve mechanism a pair of admission valves, oppositely disposed valve stems connected to said valves to actuate them, an oscillatory cam member located in the steam chest and provided with symmetrically disposed cam surfaces, each valve stem having cooperative engagement with its adjacent cam surfaces, a spring connecting the two valve stems to hold each in cooperative engagement with its cam surface.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

IVitnesses-p R. C. FosDIoK, W. R. BROWN.

five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

